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Does Fentanyl Cause Bradycardia?

Peter Manza, PhD profile image
Reviewed By Peter Manza, PhD • Updated Aug 14, 2023 • 5 cited sources

Fentanyl causes bradycardia (slow heart rate). In official prescribing documents for the prescription medication Duragesic, which contains fentanyl, doctors are advised that the drug can cause a slow heart rate.[1] Healthcare professionals are encouraged to monitor their patients closely for this known problem. 

If you’re misusing fentanyl, a doctor may not monitor your heart for damage. Each dose you take could cause a little more harm, and in time, you could cause irreversible damage.

Here’s what you need to know about fentanyl and your heart:

What Is Bradycardia?

Every tissue in your body relies on a fresh, constant supply of blood. Each time your heart beats, it delivers nourishment to the cells deep inside your body. Fentanyl slows your heart, complicating this process. 

Bradycardia is technically defined as a pulse slower than 60 beats per minute.[2] But each person’s body is different. If your pulse is typically 80 beats per minute and drops to 65, you could be experiencing bradycardia.

Some people don’t notice a slow heartbeat. But you could experience the following symptoms:

  • Fainting or swooning
  • Fatigue, especially when exercising
  • Chest pain 
  • Confusion
  • Dizziness
  • Shortness of breath 
  • Weakness

Bradycardia caused by fentanyl typically worsens when the drug is active and eases when you’re sober. But as opioid use disorders (OUD) deepen, you may never achieve full sobriety. Your heart may always beat slightly too slowly. 

How & Why Does Fentanyl Cause Bradycardia?

Opioids like fentanyl latch onto receptors in the brain, causing relaxation and euphoria. Other opioid receptors are located within your heart and nervous system. Latching is responsible for altering the speed of your heartbeat.

Researchers say opioids latching to cardiac receptors slow the heartbeat directly. And opioids attaching to major systems (like your vagus nerve) can change electrical impulses that drive your heartbeat.[3] If your heart gets signals to beat slowly, and the muscles are relaxed and sluggish, your heart rate slows dramatically.

Fentanyl can also produce a dream-like state in which breathing rates slow and you’re less responsive to the world around you. Just as your heartbeat slows when you’re asleep, it can slow when you’re high.

Understanding Fentanyl Use & Palpitations

Your heart should beat in smooth, predictable patterns that push blood throughout your critical tissues. Researchers say fentanyl can change this process. 

In a study of 850,000 people, researchers found a link between opioid use and atrial fibrillation, a problem with heart rhythms.[4] Instead of contracting in a smooth and controlled manner, opioid users had hearts that quivered and trembled. 

Heart palpitations like this cause blood to pool inside your blood vessels and tissues. Sluggish blood can lump and clot, raising the risk of serious complications like heart attacks and strokes. 

Heart palpitations are serious, and they suggest a cardiac electrical system that isn’t working properly. The more fentanyl you take, the more likely this complication is.

You may notice palpitations, as they can make you feel nervous or unbalanced. Sometimes, they cause chest pain too. 

Other Heart Issues Associated With Fentanyl Abuse

Researchers say using fentanyl is associated with a higher risk of heart attack, independent of other risk factors.[5] In other words, using opioids can harm your heart, even if you don’t have other health problems associated with cardiac disease.

Changes in your heart rate are primarily responsible for an increased heart attack risk. But researchers also mention that people using opioids push less blood out with each beat, causing even more damage. And the stress associated with quitting and relapsing could harm your heart too.

The best way to preserve your health is to address OUD through science-based therapies, such as Medication for Addiction Treatment (MAT) programs using therapies like Suboxone. You’ll get the help you need to attain and maintain your sobriety over the long term in a program like this.

Reviewed By Peter Manza, PhD

Peter Manza, PhD received his BA in Psychology and Biology from the University of Rochester and his PhD in Integrative Neuroscience at Stony Brook University. He is currently working as a research scientist in Washington, DC. His research focuses on the role ... Read More

  1. Duragesic Prescribing Information. U.S. Food and Drug Administration. October 2019. Accessed March 2023.
  2. Bradycardia: Slow Heart Rate. American Heart Association. November 2022. Accessed March 2023.
  3. Cardiac Effects of Opioid Therapy. Pain Medicine. October 2015. Accessed March 2023.
  4. Opioid Use May Increase Risk of Dangerous Heart Rhythm Disorder. American Heart Association. November 2018. Accessed March 2023.
  5. Opioid Use Is Associated with Increased Out-of-Hospital Cardiac Arrest Risk Among 40,000 Cases Across Two Countries. British Journal of Clinical Pharmacology. May 2022. Accessed March 2023.

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